Mix warm milk and yeast on low speed with a dough hook. Add flour and salt gradually, mix on low speed for about 2 minutes until the dough forms a ball.
Add softened butter and mix again on low speed until butter is fully incorporated - about 2 minutes. Dough will look dry and tough.
Knead dough by hand until it becomes soft and smooth - about 5 minutes. The dough will be slick but not sticky.
Transfer dough back to the bowl and allow it to rise in a warm place until doubled in size— about 1 - 1½ hours.
Assembly
Once dough has doubled in size, roll out into a rectangle - approximately 8” wide, 15” long and ¼” thick.
Combine brown sugar and cinnamon. Spread evenly over the dough.
Roll dough tightly into a log and transfer to a buttered loaf pan. Allow to rise for another 1 - 1 ½ hours.
Preheat oven to 375°F.
Brush top of dough with milk and bake uncovered on the middle rack for 25 - 30 minutes, or until the top is golden brown.
Cool bread for at least 30 minutes before slicing. Run a knife around the edges to remove from pan.
Store bread in an airtight container at room temperature for up to 3 days.
Notes
If using active dry yeast, allow milk and yeast to sit for 5 minutes before adding remaining ingredients.